X-Ray Emission from Synchrotrons vs. Cyclotrons

[oldmisery]

Why do accelerating electrons (synchrotron) emit x-rays, but accelerating protons (cyclotron) don't? Both are accelerating/decelerating charges.

 

[Bob S]

The emission power of synchrotron radiation depends on the relativistic Lorentz factor γ to the fourth power, so 10 GeV electrons radiate much more than 10 GeV protons, other factors being the same. See

http://hyperphysics.phy-astr.gsu.edu/hbase/particles/synchrotron.html

Protons do radiate synchrotron radiation. It is expected to be a serious problem in LHC at full energy (7 GeV per beam), because the proton synchrotron radiation is soft x-rays, that cause residual gas atoms adsorbed to the beam tube walls to desorb, causing a vacuum pressure rise and proton residual gas scattering and beam loss.

Bob S

 

[nasu]

They do. As any other charged particle when accelerated.
The power emitted is many order of magnitude lower than for electrons of the same energy.

See here, for example:
http://hyperphysics.phy-astr.gsu.edu/hbase/particles/synchrotron.html

 

[oldmisery]

Thanks to both for the reference, it's a great help.

 

[sardar]

There are several factors that contribute to the difference in X-ray emission between synchrotrons and cyclotrons. One key factor is the mass difference between electrons and protons. Electrons have a much smaller mass compared to protons, which means they can be accelerated and decelerated more easily. This results in a larger change in their velocity, which is a key factor in the emission of X-rays.

In addition, the acceleration process in synchrotrons is much more gradual compared to cyclotrons. In synchrotrons, electrons are accelerated in a circular path, gradually increasing their energy as they pass through accelerating structures. This gradual acceleration process allows for a smoother transition between energy levels, resulting in a more efficient emission of X-rays.

On the other hand, in cyclotrons, protons are accelerated using a series of alternating electric fields. This rapid acceleration process results in a more abrupt change in the proton's velocity, limiting the efficiency of X-ray emission.

Another important factor is the emission mechanism itself. In synchrotrons, X-rays are emitted through a process called synchrotron radiation, where the acceleration of electrons produces a strong magnetic field that causes them to emit photons in the X-ray range. This process is not present in cyclotrons, which means protons do not emit X-rays in the same way.

Overall, the difference in X-ray emission between synchrotrons and cyclotrons can be attributed to the mass difference between electrons and protons, the gradual acceleration process in synchrotrons, and the specific emission mechanism involved. These factors demonstrate the complex nature of particle accelerators and the importance of understanding their design and operation in order to effectively utilize them in scientific research.